The invention relates generally to computer networks, and more specifically to determining information representative of computer network topologies.
Network managers typically use commercially available network monitors or probes that are attached to the segments to collect the information about traffic over those segments. From a central location or distributed locations, the network manager periodically polls those monitors for the data that they have collected. With this collected data from the monitors, the network manager can use a reporting package to generate various reports about the operation and performance of the network. For example, often it is desirable to generate a report about the traffic load on each network segment or machine/server so as to identify overloaded segments and/or equipment which may have too many active nodes attached to them and under-utilized segments and/or equipment to which it may be desirable to transfer active nodes. However, to make an accurate report of the traffic that is generated and access patterns by nodes attached to a given segment, it is necessary to have some knowledge about which nodes are attached to which segments.
One common approach has been to provide a map of the network to the network manager's computer. Thus, the network manager knows a priori were every node is initially located and that information can be used to generate reports about network performance and utilization. Another approach is to use a commercially available tool which generates a map of the network by using what is referred to as a ping sweep. There are several problems with such approaches however. First, these approaches are generally quite slow. Secondly, the network manager has to determine where all of the nodes are located and then enter that information into the system. Thirdly, not all protocols have a ping capability. And fourth, if nodes are moved or the network reconfigured, the map immediately is out of date and must be revised before accurate and reliable reports about network activity and performance can be generated. Particularly in large networks, it is not at all unusual for nodes to be moved to different locations, for segments to be added or removed, and for other similar changes to be made to address the changing needs of the community that is using the network or to address local problems in the subnetworks which make up the entire network. Unfortunately, the network manager often is not aware of some of these changes so he or she will not know that the map that was originally entered is no longer accurate or, if that is known, how to change it to accurately reflect the new topology. Moreover, if the network manager is not aware that the topology of the network has changed, he or she may use erroneous information from an out-of-date map.
An alternative approach has been to use complex algorithms to create an actual map of the network. But such algorithms are time consuming and are prone to error.
Thus, there is a need for a better, efficient way of discovering what a network's topology is and using that information to help in generating reports about the network.